Acute nephritis may be caused by tonsillitis, acute upper respiratory tract infection, viral infection and so on. 1. Tonsillitis: because bacteria will be infected when tonsillitis. After entering the bloodstream and becoming humoral antigens, antibody antigens will form immune complexes in the body fluids. When passing through the blood circulation and flowing through the kidneys, it will be deposited on the glomeruli, leading to acute nephritis. 2. Acute upper respiratory tract infection: especially acute upper respiratory tract infection caused by streptococcus. It can be manifested as acute nephritis by the increase of foam in urine, hematuria, blood lipids in blood and abnormal blood pressure. 3. Viral infection: due to the formation of immune complexes after viral infection, these immune complexes will be deposited on the glomeruli, thus causing kidney damage, thus causing acute nephritis. Patients with acute nephritis should go to the nephrology department of regular hospitals in time to receive targeted treatment under the guidance of professional doctors.